Generally, human skin is composed of an outer skin layer, an inner skin layer, and a hypoderm skin layer, and the outer skin layer is composed of keratinocyte layer, a transparent cell layer, a granule-cell layer, a prickle-cell layer and a basal cell layer, wherein a barrier zone like a strong fortification is present between the transparent cell layer and the granule-cell layer.
Therefore, regeneration of skin depends on the barrier zone, that is, whether or not nutrition substances permeate this protective layer and reach to the inner skin. However, the nutrition substances cannot permeate the barrier zone and be soaked into the inner skin, and only the keratinocyte layer is supplied with moisture except nutrition components.
In order to solve this problem, Liposome has been suggested and widely known for skin regeneration effect. However, the Liposome is proved not to permeate the barrier zone. According to papers published by American Academic Skin Institute in U.S.A., cosmetics should reach to the inner skin beyond the barrier zone to regenerate the skin.
Liposome can not reach to the inner skin, and supply moisture components to the keratinocyte layer.
Further, in case of mercury, hormone, and vitamin A,D and E, even though they can permeate the barrier zone, they have no particular good effect to improve the facial skin. Especially, it is well known that the mercury or the hormone may cause serious ill side effects.